First report of Rhodnius montenegrensis (Hemiptera, Reduviidae, Triatominae) in Amazonas, Brazil

Abstract

INTRODUCTION:

Triatomines are hematophagous insects of epidemiological importance because they are vectors of Chagas disease. We present here the first report of Rhodnius montenegrensis in Amazonas, Brazil.

METHODS:

Triatomines were collected from Attalea butyracea palm trees in the municipality of Guajará.

RESULTS:

Two adult female R. montenegrensis specimens were identified.

CONCLUSIONS:

The present study confirms that the number of triatomine species within the Amazon has increased from 10 to 11, and the number of Brazilian states with R. montenegrensis has increased from two to three.

Keywords:
Western Amazon; Chagas disease; Triatomines

Triatomines are hematophagous insects belonging to the Reduviidae family and the Triatominae subfamily¹. They are found throughout South and Central America and are of epidemiological importance as they are vectors of Trypanosoma cruzi, the etiologic agent of Chagas disease (American trypanosomiasis)¹. These vectors may also transmit the protozoan, Trypanosoma rangeli, to vertebrates; although this species does not cause symptoms of infection in humans, it may complicate differential diagnosis of T. cruzi².

Currently, 154 triatomine species, grouped into 19 genera^3-5, have been identified worldwide. Of these, over 30 species, distributed among nine genera, occur within the Amazon region⁶. In the Brazilian state of Amazonas, ten species, distributed among four genera, were previously recorded: Cavernicola lenti Barrett and Arias, 1985, Eratyrus mucronatus Stal, 1859, Panstrongylus geniculatus (Latreille, 1811), P. lignarius (Walker, 1873), P. rufotuberculatus (Champion, 1899), Rhodnius amazonicus Almeida, Santos, and Sposina, 1973, R. brethesi Matta, 1919, R. paraensis Sherlock, Guitton and Miles, 1977, R. pictipes Stal, 1872 and R. robustus Larrousse, 1927⁷. The present article reports the first occurrence of R. montenegrensis in the Brazilian state of Amazonas.

In January 2019, using a dissection technique, triatomines were collected from four Attalea butyracea palm trees (commonly referred to as Jaci or coquinho da mata in the Amazon region) in a rural area of the municipality of Guajará, Amazonas, near the river Juruá (latitude 07º 30' 87''S, longitude 72º31'17''W). This municipality is located in the meso-region of the southwestern Amazon and the micro-region of Juruá.

Two triatomines were collected and transferred to the Laboratory of Tropical Medicine at the Federal University of Acre (UFAC) in the city of Rio Branco, Acre, where they were identified based on their morphological characteristics, previously described by Lent and Wygodzinsky⁸ and Rosa et al.⁹. These two specimens were subsequently identified as female R. montenegrensis and referred to the Entomology Laboratory of the Department of Biological Sciences, School of Pharmaceutical Sciences, Paulista State University Júlio de Mesquita Filho (UNESP), Araraquara, São Paulo, Brazil, where the species were further confirmed by genital charactersistics¹⁰ (Figure 1A-D). These R. montenegrensis individuals (two adult females, municipality of Guajará, Amazonas, Brazil, latitude 07º 30' 87''S, longitude 72º31'17''W, Madeira, F.P, col. Oliveira J, det.) were then added to the Triatominae collection, "Dr Jose Maria Soares Barata" (CTJMSB) of the UNESP, Araraquara.

Collected R. montenegrensis individuals were mainly yellow in color with black longitudinal stripes on the pronotum, wings, and connexivum⁹ (Figure 1A). Markings on the head included a distinct central yellow band between two continuous brown bands; stains from the climax regions to the neck were not present⁹ (Figure 1B). Legs were yellow in color, except for the posterior tibias, which had a black stripe near the tarsus⁹(Figure 1A).

FIGURE 1:
Female specimen of Rhodnius montenegrensis collected from Attalea butyracea palm trees in the municipality of Guajará, Amazonas, Brazil. (A) Dorsal view. (B) Head. (C) Detail of the pronotum. (D) Ventral view. (E) Female genitalia.

R. montenegrensis specimens were further analyzed for Trypanosoma sp. infection. Fresh intestinal content in a 0.9% saline solution was examined using optical microscopy (400x magnification)¹¹. R. montenegrensis specimens were not positive for trypanosomatids, however.

This is the first report of R. montenegrensis in Amazonas. This species was first described in the municipality of Monte Negro, Rondônia⁹, and it was further recorded in two meso-regions in the state of Acre^1,12. Given the results of the present report, the number of triatomines occurring in the state of Amazonas has increased from 10 to 11, expanding the distribution of this species in Brazil, which previously only comprised the states of Rondônia and Acre (Figure 2).

FIGURE 2:
Distribution of Rhodnius montenegrensis in Brazil.

Although in the present study, R. montenegrensis specimens were not infected by trypanosomatids, this species is nonetheless a potential vector for transmission of this etiological agent given that its infection by T. cruzi¹³ and T. rangeli² was previously confirmed. R. montenegrensis individuals infected by T. rangeli were further found inside apartments in the state of Acre, but without evidence of domiciliation¹⁴.

The occurrence of T. cruzi-infected R. montenegrensis individuals indicates that this triatomine has an active role in the maintenance of the enzootic cycle of this trypanosomatid^13,15, thus reinforcing the need for further studies on R. montenegrensis occurrence to further elucidate its distribution and overall ecology.

ACKNOWLEDGEMENTS

The authors would like to thank the Acre State Research Support Foundation (FAPAC) and the Dean of Research and Post-Graduation (PROPEG) at the Federal University of Acre (UFAC).

REFERENCES

• ¹
  Meneguetti DUO, Tojal SD, Miranda PRM, Rosa JA, Camargo LMA. First report of Rhodnius montenegrensis (Hemiptera, Reduviidae, Triatominae) in the State of Acre, Brazil. Rev Soc Bras Med Trop. 2015;2015(48):471-3.
• ²
  Meneguetti DUO, Soares EB, Campaner M, Camargo LMA. First report of Rhodnius montenegrensis (Hemiptera, Reduviidade, Triatominae) infection by Trypanosoma rangeli Rev Soc Bras Med Trop . 2014;47(3):374-6.
• ³
  Oliveira J, Alevi KCC. Taxonomic status of Panstrongylus herreri Wygodzinsky, 1948 and the number of Chagas disease vectors. Rev Soc Bras Med Trop . 2017;50(3):434-5.
• ⁴
  Lima-Cordón RA, Monroy MCC, Stevens L, Rodas A, Rodas GA, Dorn PL, et al. Description of Triatoma huehuetenanguensis sp. n., a potential Chagas disease vector (Hemiptera, Reduviidae, Triatominae). ZooKeys. 2019;820(1):51-70.
• ⁵
  Poinar Jr G. A primitive triatomine bug, Paleotriatoma metaxytaxagen en. et sp. nov.(Hemiptera: Reduviidae: Triatominae), in mid-Cretaceous amber from northern Myanmar. Cretac Res. 2019;93(1):90-7.
• ⁶
  Ribeiro Castro MAL, de Souza Castro GV, de Souza JL, de Souza CR, Ramos LJ, de Oliveira J, et al. First report of Pantrongylus megistus (Hemiptera, Reduviidae, Triatominae) in the State of Acre and Rondônia, Brazilian Amazon. Acta Trop. 2018; 182:158-60.
• ⁷
  Gurgel-Gonçalves R, Galvão C, Costa J, Peterson AT. Geographic distribuition of chagas disease vectors in Brazil based on ecological niche modeling. J Trop Med. 2012;2012(1):1-15.
• ⁸
  Lent H, Wygodzinsky PW. Revision of triatominae (Hemiptera, Reduviidae) and their significance as vectors of Chagas’ disease. Revision of triatominae (Hemiptera, Reduviidae) and their significance as vectors of Chagas disease. Bull Am Mus Nat Hist. 1979;163(1):123-520.
• ⁹
  Rosa JA, Rocha CS, Gardim S, Pinto MC, Mendonça VJ, Ferreira-Filho JCR, et al. Description of Rhodnius montenegrensis n. sp. (Hemiptera: Reduviidae: Triatominae) from the state of Rondônia, Brazil. Zootaxa. 2012;3478(1):62-76.
• ¹⁰
  Rosa JA, Mendonça VJ, Gardim S, Carvalho DB, Oliveira J, Nascimento JD, et al. Study of external female genitalia of 14 Rhodnius species (Hemiptera, Reduviidae, Triatominae) using scanning electron microscopy. Parasit Vectors. 2014;7(17):1-10.
• ¹¹
  Ramos LJ, Souza JL, Souza CR, Oliveira J, Rosa JA, Camargo LMA, et al. First report of Triatoma sordida Stal, 1859 (Hemiptera, Reduviidae, Triatominae) in the State of Acre and Brazilian Western Amazon. Rev Soc Bras Med Trop . 2018;51(1):77-9.
• ¹²
  Jesus AC, Madeira FP, Moraes MHS, Morais AA, Moresco GG, Oliveira J, et al. Increased geographical distribution of Rhodnius stali and Rhodnius montenegrensis: First report in the Juruá Valley region, Acre, Brazil. In: Salgado YCS, Oliveira, AC, editors. Pathologies: parasitic diseases. 1st ed. Ponta Grossa: Athena; 2019. p. 25-34.
• ¹³
  Bilheiro AB, Rosa JA, Oliveira J, Belintani T, Fontes G, Medeiros JF, et al. First report of natural infection with Trypanosoma cruzi in Rhodnius montenegrensis (Hemiptera, Reduviidae, Triatominae) in Western Amazon, Brazil. Vector Borne Zoonotic Dis. 2018;18(11):1-6.
• ¹⁴
  Ribeiro MAL, Castro GVS, Souza JL, Rosa JA, Camargo LMA, Meneguetti DUO. Occurrence of triatomines in an urban residential complex in the municipality of Rio Branco, Acre, South-Western Amazon. Rev Soc Bras Med Trop. 2019;52(1):1-4.
• ¹⁵
  Bilheiro AB, Oliveira J, Bellintani T, Fontes G, Junior A, Meneguetti DUO, et al. Biological aspects of Rhodnius montenegrensis (Hemiptera, Reduviidae, Triatominae) under laboratory conditions. Vector Borne Zoonotic Dis . 2019;20(20):1-4.

• Ethical considerations: Triatomine collection was carried out under a permanent license issued by the Brazilian Institute of the Environment and Renewable Natural Resources (IBAMA) (License no. 52260-1).
• Financial support: This study was supported by the Research Program for the Single Health System (SUS): Shared Health Management (PPSUS) of the Acre State Research Support Foundation (FAPAC).

Publication Dates

• Publication in this collection
  16 Mar 2020
• Date of issue
  2020

History

• Received
  16 Sept 2019
• Accepted
  12 Dec 2019